Lipid Oxidation Levels in Different Parts of the Mackerel,Scomber scombrus

Abstract

The estimation of the lipid oxidation levels in fish is frequently done using the thiobarbituric acid method. The usual reporting method refers to the amount of malonaldehyde (MA) found per fresh weight of fish, which introduces a certain bias because MA is derived solely from the fat content of the fish, and the range of fat content in different fish may vary from 0.5 to 30%. The sampling procedure may use several whole small fish, a single fillet in a medium sized fish, or any portion of a larger sized fish. Bias may be introduced, especially when dealing with fish in which only a random sample is utilized, since different parts of the fish contain differing amounts of fat and the rate of lipid oxidation in different anatomical Darts is not uniform. ~a c k e r e l (weighing 500-600 g) were kept frozen at -18OC and, at different times. s a m~l e s (n = 4) were taken and the TBA value and fat content were determined in three dorsal (cranial, medial and caudal) and three ventral (cranial, medial and caudal) samples of approximately the same length.The results show clearly that MA content expressed per total weight is similar in the ventral and dorsal sections, however when the MA content is expressed per fat weight, the dorsal sections show an MA content higher than the ventral sections by some 50% in the cranial and medial areas. In the caudal area dorsal and ventral sections do not show a significant difference in MA content, both being higher than the MA content ili cranial and medial sections. The fat content of the ventral section was significantly higher than the dorsal section in both the cranial and medial sections.The results show that in mackcrel, the lipid oxidation level is not uniform in different sections and the caudal scctions have the highest lipid oxidation level. From these results, the proposition arises that a better estimation of the lipid oxidation level would be obtained by expression of the MA content per fat weight, and that the most oxidized part in each fish should be used as the sampling site for the determination of the lipid oxidation level. This should provide a certain safety margin, knowing that the highest possible value in any given sample is being determined. [Article copies available for a fee j n m The Haworth Document Delivery Service: 1-800-342-9678. E-mail address: getinfo@haworfh.com]

Comparison of malondialdehyde concentrations in different muscle areas of tench Tinca tinca L

“…Significant MDA accumulation was observed in females that weighed more than males and that, according to Jirásek and Laudát (1984), have a larger proportion of head to the rest of the body compared to males. Icekson et al (1998) observed a non-uniform MDA concentration in mackerels (Scomber scombus). He determined fat content and MDA concentration in three segments of the body -cranial, medial, caudal -after reaction with thiobarbituric acid (TBA).…”

“…Fat content in the cranial and medial segments was higher in the ventral than in the dorsal area. The above-mentioned results by Icekson et al (1998) were obtained using MDA calculation related to fat content (in wet tissue). When expressed in terms of total weight of the fish, MDA concentrations in dorsal and ventral areas of the segments were similar.…”

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“…This is due to the fact that the malondialdehyde can react with other fish components as nucleosides, nucleic acid, proteins and phospholipids. On the other hand, this reaction may vary depending on the type of fish (Icekson et al, 1998).…”

Post-mortem storage conditions and cooking methods affect long-chain omega-3 fatty acid content in Atlantic mackerel (Scomber scombrus)

“…Fish were immediately euthanized by immersion in a 1 mL.L -1 eugenol bath (Fili@vet Reseau Cristal, France) for 5-10 min, then immediately labelled for later identification, and dissected on board. Sampling was restricted to the dorsal fillet from the right side of the fish (i.e., white muscle under the first dorsal fin).This area is homogenous in both lipid content and lipid oxidation in S. scombrus (Icekson et al, 1998), and in lipid and fatty acids contents in the related species S. japonicus and S. australasicus (Bae et al, 2010).…”